It depends who's reading it. The whole genre of titles "* you don't know", "you're wrong about *" is condescending and frequently false.
I suspect that's what the parent post was referring to and I would agree: percentile calculations do work the way I think, and the article didn't say anything controversial.
I'm the article's author. I don't think the headline HN chose is great but I don't mind if people have different interpretations of what I write. Hopefully all the commenters here are actually reading the original article and judging it on its merits (and flaws), right? right?
I suspect that's what the parent post was referring to and I would agree: percentile calculations do work the way I think, and the article didn't say anything controversial.